1. Field of the Invention
The present invention relates to a voice recognition dictionary generation apparatus and a voice recognition dictionary generation method, and more specifically, to generating a voice recognition dictionary with an improved processing efficiency when generating and using the voice recognition dictionary.
2. Description of the Related Art
Systems with a function of reading a text input thereto aloud (Text To Voice (TTS) engine) have been developed and widely used for a mobile phone answering service and so on. For example, in a portable service for individual users, such a system is used for a voice service of reading out information including e-mails, news articles, and market trends in response to a phone call when the user does not have any mobile terminal or a computer at hand.
Music is reproduced based on audio information by connecting a device that stores therein the audio information for reproduction to an audio device. An example of such audio information may be music data, and the music data includes tag data describing information such as a title of music, an artist name, and the like, along with digital data of the music. It has become possible to display the title of the reproduced music on a display screen based on the tag data, and to read out the title using the TTS engine. Furthermore, it has also become possible that a user enters the title of the music through voice to reproduce the music.
In order to recognize the voice spoken by the user, a voice recognition dictionary that stores therein adequate words (keywords) to be used is required. Japanese Patent Application Publication No. 2001-309257 discloses a related technique of, in order to facilitate a program search in digital television broadcasting, extracting a keyword to perform the program search from program guide information based on words corresponding to a specific word class, generating a voice recognition dictionary including reading of each keyword, and searching for a program by a voice input.
Japanese Patent Application Publication No. 2004-053979 discloses a technique of generating a voice recognition dictionary that stores therein pronunciation data that is matched with the user's pronunciation by performing a process of replacing a letter that the user does not pronounce or a letter of which pronunciation data cannot be generated by the TTS with a space, and the like.
Japanese Patent Application Publication No. 2008-275731 discloses a technique of, to generate a dictionary of recognized vocabulary, storing a part of a character string of a word and pronunciation symbols corresponding to the part as a segment pair, and generating a string of the pronunciation symbols very likely to be pronounced by the user using an occurrence probability based on the occurrence rate of the segment pair.
There is a case where a new word that is not stored in the dictionary is spoken after the voice recognition dictionary described above is generated. The new word is required when, for example, new information is used after a new music such as a newly released music compact disc (CD) is added or a new phone number is added to an address list in a mobile phone. In such a case, the voice recognition dictionary needs to be updated to include the new words.
When a part of the information (for example, one line item in the address list or one music piece in the music CD) is updated, it is generally adapted to update not only the new data but the entire data. Therefore, compared with a case of updating only the added data, it takes disadvantageously longer to generate the recognition dictionary.
On the other hand, when a part of the recognition dictionary is updated, a new file is generated every time the information is updated. To use the voice recognition dictionary, these files are accessed and the updated information in the corresponding file is used. At this time, if the number of the files is small, an affect on processing time of the voice recognition may be small, but if the number of the files is large, the processing speed decreases.